Game Load to 95% and Freezes’

[brp51d]

After much testing my 95%loading problem occurs mostly when plying a missin with spitfire 1a or 2a. Whenever I set those planes to fky, the mission will not load. Also, I tried to set effects at high. Mission would not load and after exit through task manager and game restart, effects were at medium. Other missisons will also fail to load. However using other planes with medium effects, mission will load about 80% os the time. GRass, foresst amd shdows are off. tried new nvidia drivers 266.58 without effect.

My system is I7@3.9
6 gigs ram
gtx580
onboard sound
win vista 64

fps is very good. 1680x1050 models,landscape high.everything else medium or low,no clouda, no AA.

I think stuttering may be sound related